Modular sealed portable digital electronic controller

ABSTRACT

An electronic digital controller, such as a load cell indicator, is disclosed in which a number of components, such as a circuit board, display, and keypad are placed within an enclosure, and the enclosure is bonded closed, such as using an adhesive, to render the enclosure watertight. The keypad is a touch sensitive, capacitive keypad with no moving parts, and it is housed behind a rigid panel. An optoelectronic transceiver allows for data exchange with an electronic memory device housed in the adhesively sealed enclosure and allows for data exchange and for updating or modification of software code housed therein. Other components, such as another circuit board, a power supply, and block connectors, are placed in an adjacent enclosure, and the circuit boards in the two enclosures are electrically connected. The power supply is preferably a potted AC power supply but may also include a battery.

[0001] This application claims priority from U.S. Provisional PatentApplication Serial No. 60/350,297, filed on Jan. 16, 2002.

BACKGROUND OF THE INVENTION

[0002] This invention relates to digital electronic controllers and,more particularly, to portable digital electronic load cell indicators.

[0003] Measuring transducers are known in the art and are used tomeasure forces associated with any number of applications involving suchthings as weight, gravity, pressure, and vibration. A load cell is acommon measuring transducer that is typically used in a wide variety ofscales or weighing systems. A load cell typically generates an analogsignal that is converted to a digital signal before being displayed orotherwise processed or used. An electronic controller, such as a loadcell indicator, is typically used to display data received from a loadcell and is often used to convert the data from analog to digital formatbefore the data is displayed or used.

[0004] Load cell indicators are well known. Most have common weaknessesthat present problems particularly when the load cell indicators areused in rough, washdown environments. In some environments, such aspoultry processing facilities, the indicators may be handled roughly andwith disdain. Cleaning crews may aim high pressure spray guns sprayinghot cleaning solution at electronic instruments for sport. This highpressure spray will often seep past gaskets and seals, leaving theinternal electrical connectors and electronic components wet. Since thecleaning solutions used are typically slightly conductive, any solutionthat finds its way to the incoming AC power connector will often resultin damage, which can range from minor corrosion of wiring and printedcircuit board traces to arc-over and destruction of the AC powerconnector and related circuitry. This damage often limits the usefullife of an instrument to mere weeks.

[0005] The personnel using the indicator as part of their daily jobfunction may also be handling sharp pointed instruments, such as knivesor scissors. They quite often use the sharp instrument instead of afinger to press buttons on a keypad. If the indicator uses a plasticmembrane keypad, which is by far the most common type of front panelfound on load cell indicators, this activity will quickly result in adamaged keypad. Depending on the design on the specific indicator, adamaged keypad may be replaced, or it may mean replacement of the entireindicator. Again, this potential for damage limits the lifetime ofindicators in some environments.

[0006] To prevent damage from the user or the environment, some loadcell indicators are mounted inside another enclosure, often with alatching flip-up transparent front lid, allowing the user to see thedisplay. To access any of the front panel controls, the user must firstunlatch the lid, lift it up, and finally press the desired key. Whilethis style of double enclosure mounting may reduce high pressure fluidinfiltration in the indicator enclosure, it also limits operator accessto the indicator, sometimes excessively so. The effectiveness of thismounting style is frequently reduced by the tendency of operators toforget to latch the front lid, leaving the indicator exposed to the veryhigh pressure spray the lid was intended to prevent.

[0007] Most digital load cell indicators have some type of display topresent weight information to the user. The choice of display can beproblematic, as many display types with outstanding visibility (such asa vacuum florescent display—VFD) have high power consumption. Indicatorsthat use VFDs often have no provision for running from battery power,limiting their usefulness as a portable device. Other indicators useseven-segment light emitting diode (LED) displays, which provide goodvisibility and reasonable power consumption, but the seven-segment styleof digit is not conducive to presenting alphanumeric data to the user.Indicators with seven segment displays are thus limited in displayinginformation, which makes setup and troubleshooting cryptic anddifficult. LCD (liquid crystal display) technology is also used in loadcell indicators. LCDs are very low power consumption devices. LCDs arealso available in character mode and dot-matrix configurations, whichallow the presentation of alphanumeric data and even graphic informationin an easily readable style. However, many digital load cell indicatorsuse LCD modules that require ambient light for the display to be visibleto the user, which makes the instrument difficult to use in dark oruncertain lighting.

[0008] Load cell indicators designed for use in washdown environmentsare often housed in stainless steel enclosures to resist corrosion. Hightemperature washdown followed by extended use in cold temperatureenvironments can lead to condensation forming on the enclosure. If theseals around the cables, display, and keypad are less than perfect, andthey usually are, condensation can also form on the inside of theenclosure, which can wet the electronic components, circuit boards, andconnectors. Display fogging is also common in this situation. Theseconditions conspire to limit the effectiveness of the indicator.

[0009] Load cell indicator enclosures designed for washdown environmentsare sometimes designed with many closely-spaced fasteners and gaskets toprevent or reduce high pressure fluid infiltration. If internal accessto the enclosure is desired, such as to replace a load cell cable orpower cable, the technician performing the procedure will spend quite abit of time and frustration removing all the fasteners and sealingmaterial to gain access to the internal connections of the indicator.

[0010] Very few load cell indicators are designed to interface with morethan one independent load cell. This limitation leads to the use ofexternal hardware, such as summing boxes, to condition multiple loadcell signals (as might be provided by a large tank or platform scale)for use with common indicators. Summing boxes are generally passivedevices, with potentiometers that must be manually adjusted to ensurethat each load cell contributes equally to the summed analog signal. Itis not uncommon for a scale technician to spend hours manually adjustinga single load cell summing box to allow an indicator to accurately weighwhen connected to a multiple load cell platform.

[0011] Some load cell indicators have provisions for interfacing withother instruments, such as bar code label printers, data collectiondevices, or computer hardware. This connection is often through a serialcommunications port. Depending on the requirement of the user, the datatransfer format between the load cell indicator and other auxiliaryinstruments, may have to be customized to the user's specificinstallation and circumstances. For many load cell indicators, this issimply not possible, as there is no allowance for field customization ofthe software code contained inside the indicator controller, and themanufacturers are unable to update software once the indicator has beenmanufactured.

[0012] Advanced or high-end load cell indicators may be used as weighingmachine controllers, in which case they are often integrated into other,more complicated machines. These machines might consist of several loadcells, other load cell indicators, various valves, slides, gates, andmotor drives, sometimes from a diverse group of manufacturers. Duringintegration and testing, problems, bugs, or unforeseen circumstanceswill often arise that require the machine controller software to bemodified. If the advanced load cell indicator/controller is not designedwith this in mind, the upgrade might require significant disassembly ofthe indicator and associated hardware to replace a physical electronicdevice containing the controller software.

[0013] Many users of load cell indicators desire a small, portableinstrument that can be mounted on a load cell platform and that can becarried by hand. This requirement limits the overall size and weight ofthe instrument and also requires a portable power source, such as abattery. Many load cell indicators do not have any provision for abattery. Some do, but require so much power that the only practicaloption is a physically large battery mounted external to the indicatorenclosure. Any externally mounted battery will require wiring to providepower to the indicator, and that wiring introduces at least twoadditional weaknesses into the system: the wiring must be sealed toprevent leakage where it enters the indicator enclosure, and exposedwiring is vulnerable to damage.

[0014] Load cell indicators used in harsh environments are oftendamaged. When this occurs, many users will desire to troubleshoot theindicator to determine the cause of the failure, and then will oftenelect to attempt a repair. Load cell indicators are relativelycomplicated and include delicate electronic instruments, sotroubleshooting may call for the use of skilled electronic techniciansand other highly trained and costly personnel equipped with anassortment of specialized tools. If the indicator does not have adequatedocumentation or if spare parts are not easily available, it may be moreeconomical to replace the entire indicator rather than to repair it. Auser or technician who may attempt troubleshooting but who may lack theproper training or the right tools can often do more harm than good whenprovided with ready access to all of the electronic components of theserelatively complex, delicate instruments.

[0015] All load cell indicators will require calibration to accuratelyweigh when interfaced with a specific load cell. Indicators are alsocalibrated at regular periods of time to meet various legal, trade, andinternal requirements. Many load cell indicators are difficult tocalibrate. The indicator calibration procedure may require variousinternal switches and potentiometers to be manually adjusted in a veryfine and precise manner. The calibration procedure may require an exactvalue of weight to be applied to the scale. Some indicators have arather lengthy and complicated calibration procedure that is not obviouswithout supplemental documentation, so if the calibration procedureinstructions are misplaced, that scale is unusable.

SUMMARY OF THE INVENTION

[0016] It is therefore an object of the present invention to provide adigital electronic controller, such as a load cell indicator, that isparticularly suited for use in a harsh washdown environment.

[0017] It is a further object of the present invention to provide a loadcell indicator of the above type that protects many key, sensitivecomponents of the indicator by permanently sealing them within awatertight enclosure such as by using an adhesive seal.

[0018] It is a further object of the present invention to provide a loadcell indicator of the above type that protects against moisture cominginto contact with high voltage within the indicator.

[0019] It is a further object of the present invention to provide a loadcell indicator of the above type that reduces the risk of damage to akeypad used in connection with the indicator.

[0020] It is a still further object of the present invention to providea load cell indicator of the above type that eliminates the keypad as apossible point entry for water or moisture.

[0021] It is a still further object of the present invention to providea load cell indicator of the above type that allows a user access to thekeypad without the need to open or close a lid or separate housing.

[0022] It is a still further object of the present invention to providea load cell indicator of the above type having a display that offersvery low power consumption while allowing the presentation ofalphanumeric data and graphic information in an easily readable style ina variety of lighting conditions.

[0023] It is a still further object of the present invention to providea load cell indicator of the above type that eliminates or greatlyreduces problems associated with display fogging.

[0024] It is a still further object of the present invention to providea load cell indicator of the above type that provides superiorprotection against water infiltration while providing easy access to anumber of its components.

[0025] It is a still further object of the present invention to providea load cell indicator of the above type that eliminates the need forexternal summing circuits or boxes or analog to digital converters.

[0026] It is a still further object of the present invention to providea load cell indicator of the above type that protects many key,sensitive components of the indicator by adhesively sealing them withina watertight enclosure.

[0027] It is a still further object of the present invention to providea load cell indicator of the above type that provides for easycustomization and updating of software code inside the indicator and foreasy data transfer to and from the indicator without the need to gainphysical access to any indicator enclosure.

[0028] It is a still further object of the present invention to providea load cell indicator of the above type that provides for easycalibration of the indicator without the need to gain physical access toany indicator enclosure.

[0029] It is a still further object of the present invention to providea load cell indicator of the above type that may be powered by AC poweror by an internal battery.

[0030] It is a still further object of the present invention to providea load cell indicator of the above type that provides users with readyaccess to some components of the indicator for easy installation andmaintenance and some troubleshooting while protectively sealing othercomponents in an inaccessible enclosure.

[0031] Toward the fulfillment of these and other objects and advantages,the present invention involves an electronic digital controller, such asa load cell indicator, in which a number of components, such as acircuit board, display, and keypad are placed within an enclosure, andthe enclosure is bonded closed, such as using an adhesive, to render theenclosure watertight. The keypad is a touch sensitive, capacitive keypadwith no moving parts, and it is housed behind a rigid panel. Anoptoelectronic transceiver allows for data exchange with an electronicmemory device housed in the adhesively sealed enclosure and allows fordata exchange and for updating or modification of software code housedtherein. Other components, such as another circuit board, a powersupply, and block connectors, are placed in an adjacent enclosure, andthe circuit boards in the two enclosures are electrically connected. Thepower supply is preferably a potted AC power supply but may also includea battery.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above brief description, as well as further objects, featuresand advantages of the present invention will be more fully appreciatedby reference to the following detailed description of the presentlypreferred but nonetheless illustrative embodiments in accordance withthe present invention when taken in conjunction with the accompanyingdrawings, wherein:

[0033]FIG. 1 is a side elevation view of a load cell indicator of thepresent invention;

[0034]FIG. 2 is a sectional view of a load cell indicator of the presentinvention;

[0035]FIG. 3 is a side elevation view of a partially disassembled frontenclosure of a load cell indicator of the present invention;

[0036]FIG. 4 is a front view of a partially disassembled rear enclosureof a load cell indicator of the present invention; and

[0037]FIG. 5 is a front view of a partially disassembled rear enclosureof an alternate embodiment of a load cell indicator of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0038] Referring to FIG. 1, the reference numeral 10 refers in generalto an electronic digital controller, such as a load cell indicator, ofthe present invention. The indicator 10 has a housing 12 comprised of afront cover 14, a base 16, and a rear cover 18 that are formed frommolded plastic and that fit together to form front and rear enclosures20 and 22 that house various components of the indicator 10.

[0039] The front cover 14 is formed by a front panel 24 and a side panelor bezel 26. The front panel 24 is produced from a transparent, rigidplastic to allow a display 28 and front panel legends 30 to be visiblefrom outside the enclosure. The front panel 24 also has one or moreareas of reduced thickness 32 aligned with keys or touch sensitive areasof a keypad 33 disposed inside the front enclosure 20. The areas ofreduced thickness 32 are formed integrally with the remaining portion ofthe front panel 24 and are also rigid. The front panel 24 is bonded,such as by adhesive bonding, to the side panel 26 about substantiallyits entire perimeter to form a watertight seal. The side panel 26 isbonded to both the front panel 24 and the base 16. A back edge of theside panel 26 and front surface of the base 16 mate together with atongue and groove fitting, and the side panel 26 is bonded to the base16 about substantially the entire perimeter of the tongue and groovefitting to form a watertight seal. It is of course understood that thefront cover 14 may be formed as a single piece or as any number ofdifferent pieces and that it may take any number of different shapes,sizes, or configurations. As used herein, it is understood that the term“bond” or “bonding” encompasses a variety of different methods offorming a watertight seal between two joined work pieces, including butnot limited to the use of adhesives or welding. For example, any numberof different adhesives may be used, including but not limited to a widevariety of glues, resins, epoxies, tapes, or foams. Similarly, anynumber of different welding techniques may be used, including but notlimited to ordinary welding, ultrasonic welding, and solvent welding.

[0040] The base 16 has any number of bosses 34 extending from its frontsurface for securing various components to be housed in the frontenclosure 20. For reasons to be described, a chute 36 is formedintegrally with and extends from a rear surface of the base 16. A backedge of the base 16 and a front edge of the rear cover 18 mate togetherwith a tongue and groove fitting. A gasket, O-ring, or similar sealingmembers are used in combination with the tongue and groove fitting toprovide a water resistant seal. Holes 38 pass through an outer peripheryof the base 16, disposed outward of the tongue and groove fittings sothat the holes 38 do not provide points of entry into either enclosure.Captive screw fasteners 40 pass through the holes 38 and are captivelyretained by the base 16. The front panel 24, side panel 26, and base 16form and bound the front enclosure 20. These components are permanentlybonded and sealed to prevent any fluid infiltration into the frontenclosure 20, and the front cover 14 and base 16 are adapted so that auser may not gain physical entry to the front enclosure 20 withoutbreaking, cutting, or otherwise piercing the base 16 or front cover 14.Similarly, the adhesive selected preferably will not allow a user toovercome the adhesive bond to gain physical access to the frontenclosure 20 and will instead require a user to break, cut, or otherwisepierce the base 16 or front cover 14 to gain physical entry to the frontenclosure 20.

[0041] The rear cover 18 has one or more openings or ports 42 along itssides or back surface to provide one or more points of entry into therear enclosure 22 for things such as an AC power cord 44, wires orcables 46 from load cells 48, and any number of other types of optionalcommunications cabling, such as to a printer, computer, another loadcell indicator, remote display, or other peripheral hardware. Seals,gaskets, or any other number of water resistant closures 50 may be usedin combination with these ports 42 to keep moisture from entering therear enclosure 22. The rear cover 18 has any number of bosses 34extending from one or more of its inner surfaces for securing variouscomponents to be housed in the rear enclosure 22. Inner partitions 52also extend from one or more inner surfaces of the rear cover 18 toprovide for further isolation of components in the rear enclosure 22.Threaded bores or holes 54 pass through an outer periphery of the rearcover 18, disposed outward of the tongue and groove fitting so that thebores 54 do not provide points of entry into the rear enclosure 22. Thethreaded bores 54 provide locations for attachment of the screwfasteners 40 so that the fasteners 40 may provide for compression of theO-ring type sealing gasket. The rear surface of the rear cover 18 alsohas a plurality of threaded bores to provide means for attaching theindicator 10 to external panels, braces, or the like 56. These threadedbores do not open into the rear enclosure 22 so that they do not providepossible locations for moisture to enter into the rear enclosure 22. Therear cover 18 and base 16 form and bound the rear enclosure 22.

[0042] The front enclosure 20 contains the majority of the electronicsfor the indicator 10, such as the main circuit board 58, display 28,keypad 33, microprocessor 59, electronic memory device, optoelectronictransceiver 60, analog to digital converter, and the like. The maincircuit board 58 is affixed to bosses 34. Since the front enclosure 20is sealed, and the front panel 24 is formed of a rigid plastic, there isno provision for an industry standard membrane keypad or mechanicalswitches. A thin opaque pre-printed polycarbonate graphic legend 30 isattached with an optically clear adhesive to the inside of the frontpanel 24. This graphic legend 30 provides for front panel 24nomenclature, which may include such information as a stylized companyand product logo, model name or number, keypad button descriptions, andlabels for the various LED indicators. The graphic layer has a windowcutout 62 to allow the display 28 to be visible. It is of courseunderstood that the graphic legend 30 may be printed directly onto thefront panel 24.

[0043] Adhered to the graphic legend plastic is the touch sensitivekeypad 33 circuit board, preferably a capacitive, touch sensitivekeyboard 33 circuit board. One side of this keypad 33 circuit board,which is attached to the graphic layer, is composed of five conductivesensing areas that serve as the touch sensitive buttons. The other sideof the keypad 33 circuit board contains the surface mount electroniccomponents, which sense the absence or presence of a finger andtranslate this to the main circuit board 58 as a key press. In thismanner, the user can simply touch his finger against certain spots onthe outside of the front panel 24 to initiate a key press.

[0044] Because this keypad 33 contains no moving parts, and theelectronic components of the keypad 33 are located inside the sealedfront enclosure 20, it cannot be easily damaged or worn out. Although acapacitive touch sensitive keypad 33 is preferred, other touch sensitivekeypads may be used, such as for example a reflective optical sensingkeypad, which detects whether or not a person's finger is present on thesensing spot. Placing the graphic legend 30 inside the transparent frontpanel 24 also serves to protect the markings and nomenclature fromabrasion and physical wear, and adhering the graphic legend 30 to thetransparent front panel 24 also reduces or eliminates fogging problemswith respect to information shown on the graphic legend 30. A smallpackage 35 containing moisture-absorbing desiccant material is alsoplaced inside the front enclosure 20 during assembly. The desiccantpackage 35 helps to ensure that the air contained in the front enclosure20 stays dry, which prevents any condensation from occurring on theinside of the transparent front panel 24.

[0045] The keypad 33 circuit board can also contain several small LEDs64. Typically, these are lit to indicate scale operating parameters,such as net, gross, or tare weight, weight in motion, or center of zeroweight. When illuminated, the LEDs 64 are visible through the graphiclegend 30 layer.

[0046] The display 28, which is a backlit liquid crystal character modedot matrix display, is physically mounted by screw fasteners on fourmolded bosses 34 of the base 16. It is electrically connected to themain circuit board 58 by soldering during assembly of the indicator 10.The display 28 of the assembled indicator 10 is visible through thetransparent front panel 24 and the window cutout 62 of the graphiclegend 30 layer. Circuits on the main circuit board 58 and softwareroutines allow the user to adjust the backlight and contrast of thedisplay 28 for good visibility in all lighting conditions. The user mayalso elect to disable the backlight to conserve power and lengthen thebattery life.

[0047] An IrDA compliant optoelectronic transceiver 60 circuit isincluded on the main circuit board 58. Together with other supportcircuitry on the circuit board and software, this transceiver 60 allowsfor serial bidirectional infrared data communications with variousexternal hardware devices. This data communication protocol is opticaland non-contact, so the indicator user can initiate a data transfer withthe indicator 10 by pointing a device such as a handheld personalcomputer/organizer at the indicator front panel 24 and executing theappropriate software routines.

[0048] An analog to digital converter component 66 is also included inthe front enclosure 20, electrically connected to the main circuit board58. The converter 66 was chosen in part for its ability to connect tomultiple analog input signals. This allows for the option of interfacingwith multiple independent load cells 48. Software routines may bepresent to calibrate and compensate each load cell 48 signal independentof the other load cells. Software routines may also be present to sumthe signals digitally if necessary. If an application uses two or moreload cells 48 as independent sensors, and the indicator 10 is programmedto simulate multiple scales, applying a weight to one load cell 48 hasno effect on any other load cell 48 in the system. In this situation,summing is not needed. If an application uses multiple load cells 48attached to a common weighing device so that an object to be weighedwill deflect multiple load cells 48, the software routines may be usedto sum the inputs from the multiple load cells 48 and to calculate thetotal weight on the weighing device. In this type of application,software routines are present to calibrate and compensate each load cell48 signal independent of the other load cells. In most cases, theability to interface with multiple load cells 48 eliminates the need forexternal analog summing circuits or boxes. If a summing circuit or boxis used, software routines may also be provided that will serve as adigital replacement for an external analog summing circuit, eliminatingthe time-consuming drudgery of manually balancing load cell 48 inputssuch as from a floor scale weighing platform.

[0049] One or more electronic memory devices 68, such as a flash memorydevice may be provided in the front enclosure 20, electrically connectedto the main circuit board 58, for storage of software programs and data.With proper software routines, the memory device 68 can be easily erasedand reprogrammed without disassembly. If the infrared datacommunications channel is used to transfer the new software to theindicator 10, the entire indicator software can be upgraded withouterror in the field by a technician or user in minutes.

[0050] A connector 70, such as a 30-pin dual row connector, iselectrically connected to the main circuit board 58 and extends into thechute 36. A portion of the connector 70 is exposed outside of the rearsurface of the base 16 for mating connection with a connector 72 that isaffixed to an interface circuit board 74. The chute 36 is sealed, suchas with an epoxy or resin, which forms a watertight seal around theconnector. The chute 36 also has to protect the connector 70. In thatregard, three grooves are provided in the chute 36 that will only matewith corresponding ramped tabs in the rear cover 18 if the two halvesare correctly positioned. Any misalignment of the two halves willprevent the tabs and grooves from engaging. This, and the fact that thechute 36 extends past the end of the connector 70 pins, protects theconnector 70 pins from damage.

[0051] It is of course understood that any number of differentcombinations of components may be disposed in the front enclosure 20 andthat not all features or elements discussed above need to be enclosed inthe front enclosure 20.

[0052] The physically accessible rear enclosure 22 contains componentsto which a user will typically need access in the field. Because it isaccessible and not permanently sealed, it is purposely of simple design.The interface circuit board 74 is located in the rear enclosure 22.Further, a few components that will typically be disposed in the rearenclosure 22, electrically connected to the interface circuit board 74,include one or more terminal block style connectors 76 or rows of suchconnectors for external devices, and connectors 78 and 80 for the powersupply 82 and optional battery 84. The interface circuit board 74 canalso provide an LED indicator that illuminates when the power supply 82is energized, electrical components for transient voltage suppression,and optically isolated modules 88 for controlling external input andoutput devices. The connector 72 is also provided, electricallyconnected to the interface circuit board 74, for mating with theconnector 70. All electrical connections to the load cell indicator 10are made through the interface circuit board 74, which is mounted in therear enclosure 22. This interface circuit board 74 is accessible to theuser for wiring external devices by removing the sealed front half ofthe indicator 10.

[0053] A power supply 82 section is provided in an upper region of therear enclosure 22 for receiving high voltage AC power and for providingappropriate voltage reduction. The power supply 82 section is set apartfrom other components in the rear enclosure 22 by the partitions 52. Thepower supply 82 section contains a watertight electrical connector thatextends through an opening in the back surface of the rear cover 18 forreceiving the incoming AC power supply (normally 120VAC). To protectagainst moisture contacting any high voltage wiring inside the rearenclosure 22, the power supply 82 is potted in an electronic grade epoxy90. When the power supply cord 44 is attached, there is no exposed highvoltage (>24VAC) within the rear enclosure 22 or front enclosure 20,which reduces the possibility of damage should moisture make its wayinto the indicator 10. Placing the power supply 82 in an upper region ofthe rear enclosure 22 also reduces the risk that water that may enterand gather in a bottom portion of the rear enclosure 22 will come intocontact with the power supply 82.

[0054] Because the indicator 10 is also intended for portable use, asealed lead acid battery 84 may also be mounted in the rear enclosure22, preferably in an upper region thereof. If a battery 84 is provided,the battery 84 will typically only provide power for the electroniccircuits when the internal power supply 82 is not energized by the ACline. Charging the battery 84 can be accomplished in at least two ways.One method would be to disconnect the latching battery connector 80 fromthe interface board, remove the battery 84 from the rear enclosure 22,and attach the battery 84 to an external charging device. This methodhas the advantage that batteries can be swapped quickly and the loadcell indicator 10 placed back in service within several minutes. Themore common method of battery charging is to provide AC power to theindicator, which will energize the internal power supply contained inthe rear enclosure 22. The power supply 82 is designed to simultaneouslypower the indicator electronics and charge the battery 84. This methodis commonly used for a semi-portable installation, where the usernormally provides AC power to the indicator 10 and only requiresportable operation on occasion.

[0055] In operation, a user will loosen the captive screw fasteners 40to remove the rear cover 18 from the base 16, gaining access to the rearenclosure 22. The user will pass one or more cables 46 from measuringtransducers 48, such as load cells, through the ports 42, electricallyconnect the cables 46 to the terminal block style connector 76, andensure that the water resistant closures 50 are sealed to inhibit orprevent the entry of moisture through the ports 42 and into the rearenclosure 22. A battery 84 may be installed or replaced, or the batterymay be connected to or disconnected from the connector 80. The user thenmates the front and rear connectors 70 and 72 and fastens the rear cover18 to the base 16 using the captive screw fasteners 40 to compress theO-ring type seal and form a water resistant seal to inhibit or preventthe entry of moisture into the rear enclosure 22. If outside AC power isrequired, the user plugs the external power cord 44 into an outlet. Theuser may then set up the indicator 10 to provide the desired displayformat using the keypad 33 and the optoelectronic transceiver 60. Theuser may also enter or retrieve data or enter, revise, or replacesoftware routines or code using the keypad 33 and the optoelectronictransceiver 60. Although not preferred, it is understood that a user mayenter or retrieve data or enter, revise, or replace software routines orcode using other serial communications ports/channels, such as by usinga cabled connection to make an electrical connection to the interfacecircuit board 74 in the same manner load cells 48 are connected, toterminals on terminal blocks 76.

[0056] In this manner, the indicator 10 of the present inventionovercomes weaknesses found in previous load cell indicators. Forexample, the permanently sealed front enclosure 20 containing the maincircuit board 58 is protected from moisture and environmentalcontamination. The power supply 82 is potted in epoxy 90 to preventfluids from coming into contact with the high voltage AC power supply82. The usual causes of keypad 33 damage and wear are eliminated by thetouch sensitive keypad 33 circuit and rigid polycarbonate front panel24. Reasonable battery life, excellent display 28 visibility andreadability, and long display lifetime are provided by the choice of abacklit liquid crystal display. The display 28 is mounted in thepermanently sealed front half of the enclosure, so there is noopportunity for display fogging or condensation. The use of captivescrew fasteners 40 to clamp the front and rear halves of the indicator10 allows for a technician to have quick access to the electricalterminals 76 for wiring external devices, such as load cells 48. Theability to interface with multiple load cells 48 eliminates in mostcases the need for external analog summing boxes. Connection to externaldata communication devices is facilitated by multiple serialcommunication ports and the ability to quickly and easily update theload cell indicator software. The software update mechanism also allowsfor modifications should the indicator 10 be integrated into othersystems. The sealed front enclosure 20 is not user serviceable, sohighly skilled technicians are not required to troubleshoot and repairthe indicator 10.

[0057] Other modifications, changes and substitutions are intended inthe foregoing, and in some instances, some features of the inventionwill be employed without a corresponding use of other features. Forexample, the indicator 10 may include or omit a battery 84 or mayinclude or omit an AC power supply 82. Further, the sealed frontenclosure 20 may contain any number of different combinations ofelements and need not contain all of the elements as described in thepreferred embodiments discussed above. Further still, although the abovediscussion related primarily to load cells 48 and load cell indicators10, it is understood that the controller 10 of the present inventionmake take any number of different configurations and may be used inconnection with any number of different devices and measuringtransducers 48. Also, although a touch sensitive capacitive keypad 33 ispreferred, any number of different keypads 33 or data entry means may beused, and the keypad 33 may be disposed in any number of locations,including externally. It is also understood that the entire disclosureof U.S. Provisional Patent Application Serial No. 60/350,297, filed onJan. 16, 2002, is incorporated herein by reference. Of course,quantitative information is included by way of example only and is notintended as a limitation as to the scope of the invention. Accordingly,it is appropriate that the invention be construed broadly and in amanner consistent with the scope of the invention disclosed.

What is claimed is:
 1. A device, comprising: a base; a first coverbonded to said base to form a watertight first enclosure; a second coverfastened to said base to form a water resistant second enclosure; afirst circuit board disposed within said first enclosure; a firstconnector electrically connected to said first circuit board; a displayelectrically connected to said first circuit board, said display beingdisposed within said first enclosure; a keypad electrically connected tosaid first circuit board, said keypad being disposed within said firstenclosure; a second circuit board disposed within said second enclosure,and a second connector electrically connected to said second circuitboard, said first and second connectors being disposed to connect whensaid second cover is properly positioned on said base.
 2. The device ofclaim 1, wherein: said bond comprises a first adhesive bond; and saidbase and said first cover are adapted so that a user may not gainphysical entry to said first enclosure without breaking, cutting, orotherwise piercing said base or first cover.
 3. The device of claim 1,wherein said keypad comprises a touch sensitive, capacitive keypad. 4.The device of claim 1, wherein: said first cover comprises a clear frontpanel; and a side panel bonded to said front panel; and furthercomprising a graphic legend, said graphic legend being bonded to saidfront panel, and said keypad being bonded to said graphic legend.
 5. Thedevice of claim 4, wherein said front panel comprises a rigid,transparent plastic, said front panel having at least one area ofreduced thickness adjacent said keypad.
 6. The device of claim 1,further comprising a potted, AC power supply disposed in said secondenclosure and electrically connected to said second circuit board. 7.The device of claim 6, further comprising a battery disposed within saidsecond enclosure and electrically connected to said second circuitboard.
 8. The device of claim 1, further comprising an optoelectronictransceiver electrically connected to said first circuit board, saidtransceiver being disposed within said first enclosure.
 9. The device ofclaim 8, wherein said optoelectronic transceiver comprises an infraredoptoelectronic transceiver.
 10. The device of claim 1, furthercomprising a plurality of captive screw fasteners, captively retained bysaid base.
 11. The device of claim 1, further comprising an erasable,programmable, electronic memory device electrically connected to saidfirst circuit board, said erasable, programmable, electronic memorydevice being disposed within said first enclosure.
 12. The device ofclaim 1, further comprising a measuring transducer, said measuringtransducer being disposed outside of said first enclosure and saidsecond enclosure and being electrically connected to said second circuitboard.
 13. The device of claim 12, wherein said measuring transducercomprises a load cell.
 14. A load cell indicator, comprising: a housingdefining a front enclosure and a rear enclosure, said front enclosurebeing permanently sealed to prevent fluid infiltration; a first circuitboard disposed within said front enclosure; a first connectorelectrically connected to said first circuit board; a displayelectrically connected to said first circuit board, said display beingdisposed within said front enclosure; a keypad electrically connected tosaid first circuit board, said keypad being disposed within said frontenclosure; a second circuit board disposed within said rear enclosure,and a second connector electrically connected to said second circuitboard, said first and second connectors being disposed to connect whensaid housing is assembled.
 15. The load cell indicator of claim 14,wherein said keypad comprises a touch sensitive, capacitive keypad. 16.The device of claim 14 further comprising a potted AC power supplydisposed in said rear enclosure and electrically connected to saidsecond circuit board.
 17. The device of claim 14, further comprising anoptoelectronic transceiver electrically connected to said first circuitboard, said transceiver being disposed within said front enclosure. 18.The device of claim 14, further comprising an erasable, programmable,electronic memory device electrically connected to said first circuitboard, said erasable, programmable, electronic memory device beingdisposed within said front enclosure.
 19. A method, comprising: (a)placing a first circuit board, a display, and a keypad in a firsthousing; (b) bonding said first housing closed to form a first enclosurecontaining said first circuit board, said display, and said keypad sothat a user may not gain physical access to said first enclosure withoutbreaking, cutting, or otherwise piercing said first housing; (c)electrically connecting said first circuit board to a second circuitboard; and (d) electrically connecting said second circuit board to ameasuring transducer.
 20. The method of claim 19, wherein: step (b)comprises, adhesively sealing said first housing closed to form a firstenclosure containing said first circuit board, said display, and saidkeypad so that a user may not gain physical access to said firstenclosure without breaking, cutting, or otherwise piercing said firsthousing; and further comprising placing said second circuit board in asecond housing and affixing said second housing to said first housing.